Increasing the number of ways to bet on, or invest in, something is likely to raise the amount someone is willing to wager on it.

Take heed, if you believe that business fundamentals drive the size of investments. Just how much people will ante is strikingly influenced by how an investment—or wager—is presented.

That's the verdict of experiments and field studies summarized in last week's Proceedings of the National Academy of Sciences by Colin Camerer, a professor of behavioral economics at the California Institute...